By Doug Schneider - @Race4caster

The rain managed to avoid Watkins Glen yesterday, passing to the north and to the south. That won't repeat today. Here's a look at the big picture radar this morning:

Movement of the rain in the image is toward the northeast (Watkins Glen is at the red dot). The first area of rain that is over western New York and northern Pennsylvania will produce some light rain at the track this morning, mainly between 8 and 10 am. Only a few hundredths of an inch can be expected from this initial round, and a period of dry conditions and partial sunshine can be expected behind it late in the morning and early in the afternoon.

A second area of rain is located over Ohio, associated with a disturbance in the mid and upper levels of the atmosphere. It is this disturbance that will bring numerous showers and storms to the track this afternoon, and it will be aided by increasing instability as temperatures warm up. The most likely time period for storms will be between noon and 5 pm, so the Prototype Challenge and Lamborghini Super Trofeo races may be impacted, with wet conditions or possibly delays. There is a slight risk of severe storms, capable of producing damaging winds and hail. While the chance of a severe storm is low, lightning and heavy rain will be the greater risks at the track today, and fans at the track need to stay aware of the weather and be prepared to seek shelter once thunder is heard. If you can hear thunder, you are close enough to be struck by lightning. 

Storms this afternoon will move east by sunset, and the overnight hours should mostly be dry. But the chance of rain will increase again on Saturday. I expect that there will be a greater impact on the racing, due to a better chance of heavier rain and strong or severe storms than today. A cold front will move across the area, and storms ahead of it are expected from the late morning into the early afternoon. Gusty winds, heavy rain, and lightning can be expected. Again, there is a slight risk that storms in the area will be severe, capable of producing damaging winds and large hail. All storms will produce lightning and heavy rainfall. If a storm passes directly over the track, a quick half inch of rain may fall.

It's a little hard to be specific on timing, but right now I think the window for the best chance of rain Saturday will be between 10 am and 4 pm. I would not be surprised if IMSA WeatherTech qualifying was cancelled. The start of the CTSC race will likely be impacted by wet conditions, or possibly delayed. 

The timing of this system is looking a little faster than before, and I'm confident that the front will be through the area Saturday evening. The storms associated with the front will be long gone by Sunday morning, however there will still be an upper level trough over the area, so I can't completely rule out the chance of an isolated shower on Sunday. It is most likely that the entire 6-hour race will stay dry. If there are showers in the area, they are most likely to occur in the mid to late afternoon when a little instability can develop, near the end or after the end of the race. 

Our radar link at the top of the page is up and running for Watkins Glen to help you stay aware of approaching storms. 

By Doug Schneider - @Race4caster

The general weather pattern hasn't changed much since my original forecast, but my confidence is increasing that there will be rain at the track on Thursday, Friday, and Saturday as a couple of low pressure systems track across the region. Sunday is actually looking pretty good, and will have the best weather of the event. The details of timing and rain amounts are still a bit uncertain, and the both of those factors will determine how much impact there will be on the racing. In any case, if you're headed to the track this weekend, you will definitely want to bring your wet weather gear along. It will come in handy at some point. 

On Thursday, moisture will begin to spread into the area from the south as a low pressure system tracks across Ontario. The question about Thursday is how quickly rain will move into the area. Over the past few days, most of the models have favored the afternoon and evening hours for rain, and this timing seems to be on track. Most of the rain may come after the practice sessions for the day are done, so I only have a low impact for Thursday even though the rain chance before sunset is high. Rain amounts around a tenth seem likely before sunset. More rain is expected after sunset, possibly another quarter of an inch.

Friday continues to be the least confident day for me as Watkins Glen will be between low pressure systems, and model agreement is poor. Although the atmosphere will be very moist, there isn't a strong mechanism in the atmosphere to produce lift for rain, and this is when the models tend to do poorly. At this time, I think there is about a 50/50 chance of seeing rain at some point in the day. With some sunshine possible at times, temperatures should warm up into the mid 80s with winds from the southwest at 10-15 mph. 

The second low pressure system will track across the Great Lakes and Ontario on Friday night and Saturday, with its trailing cold front moving through Saturday night. With the warm, moist air mass in place and lift provided by the approaching front, I expect numerous showers and thunderstorms around the track on Saturday. Timing of the best rain chances is tough to pinpoint this far out, as it looks like there could be storms at any time during the day. Rainfall amounts could be somewhere in the range of 0.25 to 0.75 inches, and the rain could be heavy at times. For this reason, I've ranked the impact on Saturday as moderate. I expect there will at least be some delays to the on track action, with some cancellations possible. 

The front will move east of Watkins Glen Saturday night, but the upper level trough will lag behind slightly, which is why I have a slight chance of rain mentioned Sunday morning. I don't think any rain on Sunday will have an impact on the race, as it will be light if it even happens at all. Clouds will be decreasing through the race, and it may be mostly sunny by the end, with temperatures getting close to 80 degrees. 

We'll have our radar link at the top of the page ready to go for Watkins Glen by Thursday. 

By Doug Schneider - @Race4caster

It appears that the weather pattern across upstate New York will be rather active later this week, which will result in at least a chance of rain each day for the Sahlen's Six Hours at Watkins Glen International. There are some uncertainties about the timing and amounts of rain, as there are some differences in the finer details between the models we use, but they do agree on the general pattern being a wet one. 

By Scott Martin - ​@RaceWx4You

First of all, I want to say a big "thank you" to you, the site regulars, for being patient on forecast updates. In my home state of Alabama, the weather has been quite active with the remnants of Tropical Storm Cindy moved onshore and now has moved off to the east coast. Rainfall amounts over the past 3 days have been incredible, with most in our state receiving over four inches, with some nearing the ten inch mark. We have also had our share of destruction, with an EF-2 tornado touching down just a few miles down the road from my location. Today I woke up relieved because I knew there would be no severe threat for me today, even with rain falling at this moment. Now let's get to the forecast.

The above image is the latest HRRR model run showing the simulated radar valid at 1PM. On this model run, this is when the most active weather will be going on across Wisconsin today. The good news is that most of the activity stays well to the north of Road America. The bad news is that there will be some scattered activity around the area. Now I do not believe that the coverage of rainfall will be as great as it shows in the model, but I think that a passing shower is possible at the track. Skies will be mostly cloudy throughout the day, and winds will be quite breezy out of the northwest at 10-15 MPH, gusting to 25 MPH at times. I'm only going with a 20% rain chance today, as the model shows much of the day being dry at the track.

There will be a line of showers and storms pushing through the area after 7PM, but I think most of the action will go south of the track. There will be a good chance of rain falling though, so campers may have to find some shelter for a little while. There may be some thunder, but nothing strong or severe is expected.

I'm going with an almost completely dry forecast for Sunday as of now. Looking at the latest model trend, there will be more showers and storms forming throughout the afternoon hours, but most, if not all, of the activity will stay west of the track until after 5-7PM tomorrow evening. Skies will be partly sunny, and winds will be out of the west-northwest at 10-15 MPH. I'm going with a 20% rain chance because I do believe it will stay dry at the track, but a stray shower is possible.

Radar is up and running on the website, so please feel free to take a look at anytime throughout the weekend. Have a great weekend!

By Scott Martin - ​@RaceWx4You

The weekend forecast for Road America at this point doesn't look too bad, but we may have to put up with a little wet stuff at some points throughout the event. Believe it or not, the tropical system that is affecting the Gulf Coast is messing with the forecast, so some of the details are not set in stone as of yet. I'll nail those down within the next day or two.

There is a surface boundary that is forecast to stall out over the Wisconsin/Illinois border, and this may bring showers and thunderstorms to the area on Thursday, especially during the afternoon hours. There is a possibility that the weather on Wednesday could make the storms form farther to the south on Thursday, we'll just have to wait and see on that part. By Friday, all of the shower activity will have moved out of the area, and the day is setting up to be nice and dry with mild temperatures.

We'll have a slightly active weather pattern setting back up over the area for Saturday as troughing starts to form and begins to move near the area. This will allow several waves to move through the area, but as of now, rain chances will be small and mainly during the afternoon hours. Same story on Sunday, but rain chances will be even smaller, and I wouldn't be surprised if I will be able to remove those rain chances out of the forecast within the next day or two.

Bottom line: We'll mention the chance of rain on both Saturday and Sunday, but more than likely it will stay dry at the track. I'll have a really good idea by Wednesday night on what the weather will hold for us at Road America.

By Doug Schneider - @Race4caster

Click images to enlarge

Perfect racing weather is expected from start to finish for the 24 Hours of Le Mans. There will barely even be a cloud in the sky. Temperatures will be pretty warm today, and a little warmer tomorrow. The forecast has played out pretty much as I expected since my first forecast last weekend, so there's not much to day other than enjoy the race!

​Here's the astronomical information for Le Mans today (from timeanddate.com):

By Doug Schneider - @Race4caster

Click images to enlarge

The weather continues to look great for the 24 Hours of Le Mans. Surface high pressure will be located near the English Channel Friday through Sunday, while a strong ridge in the mid and upper levels of the atmosphere will be across France. This ridge is trending a little stronger in the latest model runs, which is why I have bumped up the temperatures a few degrees for today's forecast update. With the strong ridge in place, there will be lots of sunshine and no chance of rain for the driver's parade on Friday and throughout race. 

I'll have a more detailed forecast of temperatures through the race on Saturday morning.

By Scott Martin - ​@RaceWx4You

Looking at the latest GFS model trend for this weekend, we'll have moisture in the Central Indiana area throughout each day, but I believe we may be able to squeeze at least two days of racing action without any interruption from Mother Nature. Even though I do have a small chance of rain for Friday, I believe we can make it throughout the day completely dry. The reason for the 20% chance is that models do not handle convective pop-up showers and storms well.

Just about the same can be said for Saturday but had to up the risk a little bit as precipitable water values will be higher, around 1.75 inches. There will be scattered shower and storm development, but I believe those will come later in the afternoon. Crossing my fingers that the on-track activity will be completed by the time those form.

More available moisture will be in the area on Sunday, with precipitable water values up around 2.00 inches. Showers and storms will be able to develop easier with the heating of the day, so there will be scattered to numerous showers around especially during the afternoon hours.

It is still early in the forecast game, but I'll be able to have a better look at what to expect when the higher resolution models come out this week. Radar will be up by Thursday on the site.